Coaxial progressive cavity pump

ABSTRACT

This invention relates a progressive cavity pump with a central feed-through for supplying steam, gas or liquids to the supply side of the pump. For the oil industry this invention enables single well stimulation. Steam can be supplied from the surface to the production zone or below through the central feed-through, heating or pressurizing oil and the surrounding formation, and facilitating production. In heavy oil fields solvents can be pumped down as well. Oil can be pumped up by the progressive cavity pump through the annulus of the connecting coaxial pipe.

TECHNOLOGY

The invention is to be applied as pump, with an internal channel throughthe rotor of the pump, for supplying heating or pressure by steam to thesupply side of the pump.

1. Objects of the Invention

Old, almost depleted, oil wells can be revived if steam is injected.Previously at least one additional steam injection well would benecessary. With this solution single wells can be continuouslystimulated by steam injection through, and below, the pump, to heat theformation and to heat the produced oil, thus keeping the viscosity lowand the oil flowing more freely. With the same reasoning, the pump canbe applied for tarsand and other heavy oil wells.

2. Background of the Invention

The US alone has over 500,000 oil wells, with an average production in2010 of only 10 barrels/day. About 300,000 wells are marginal wells withan average of about only 2 bbl/day production. Still just the marginalfields together produce about 700 million bbl/year, about half theimports from Saudi-Arabia. Doubling the marginal field production wouldbe helping energy independence, as well as an economic stimulus.

A non-Moineau progressive cavity pump is known from my patent NL 2004120(20, Jul. 2011). This pump can be used with all metal parts, at muchhigher rpm's, and with much better balancing, thus much less vibrations.The pump is based as on a central oval rotor, and sections of housingwith 2 rockers, helically spiraling around this rotor, thus creating 8progressing cavities.

A feature not obvious from above patent is the lack of need for anuniversal joint or gear, as needed with Moineau pumps. And as such it isnot obvious a simple opening inside the rotor can act as feed-throughfor steam, gas or liquid. Thus steam can be pumped below the pump,heating the formation, letting oil flow more freely, and keeping oilflowing more freely up the well. For this the pump has to be connectedto a coaxial pipe, with the inner pipe transporting hot steam or solventthrough the rotor, and the annulus transporting pumped oil.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 front view of hollow elliptical rotor and two straight-edgedrockers

FIG. 2 exploded view with most of the housing sections removed

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-section of a machine comprising in essence of onerotor (3), two rockers (2) and a housing (1), creating inside thehousing eighth separate variable volumes. The hollow rotor (3) has acavity (4) which allows transport through the rotor, for example forinjecting hot steam from the surface below the pump.

FIG. 2 shows an exploded view with all but 5 housing sections removed.It shows how the rockers are wrapped around the rotor.

1. A progressive cavity pump consisting of in essence one axiallyuniform rotor of oval shape and sets of two rockers with straight-edgedshape and housing, with an isolated cavity through the rotor connectingboth sides of the pump, to be used for supplying gas or liquid to thesupply side of the pump.
 2. A progressive cavity pump consisting of inessence one axially uniform rotor of oval shape and two rockers withstraight-edged shape and one housing, with an isolated cavity throughthe rotor connecting both sides of the pump, to be used for supplyinggas or liquid to the supply side of the pump.
 3. A progressive cavitypump of claim 1 or 2, where the shape of the rotor changes in axialdirection to allow for compression or decompression.